Gas engine



FIG. 1 is a front perspective view of a gas engine showing my new design.

FIG. 2 is a side elevational view thereof.

FIG. 3 is a bottom plan view thereof.

FIG. 4 is a top plan view thereof.

FIG. 5 is a front elevational view thereof.

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a gas engine, as shown and described. 